The present invention relates to drafting equipment with small double belts for spinning machines with a fiber bundling zone which follows a pair of output rollers and is followed by a pair of delivery rollers. Drafting equipment of this type is described in DE 43 23 472 (U.S. Pat. No. 5,600,872). Therein a pneumatic compression device is installed between the pair of output rollers and the pair of delivery rollers, said compression device being provided with a small perforated belt and a suction device extending on the side of the small belt away from the fiber sliver and aspiring air through the fiber sliver.
Very good results are achieved with this known device with respect of gathering together and bundling of the fibers, so that a smooth yarn with considerably improved resistance to tearing is spun. It was shown, however, that the pneumatic compression device has relatively high air consumption. When using the conventional traversing apparatus, it may furthermore occur that border fibers are no longer seized securely because they are either outside the perforation zone, or because the negative pressure is not sufficiently strong to bundle them. An enlargement of the perforation zone not only requires more air but decreases the gathering together of the fibers. Increased negative pressure also required more suction capacity. It is however also important for the obtention of uniform spinning results that the optimal state of the drafting equipment, in particular of the compression device, be maintained.
In the known device, a small belt is used without fabric insert in order to release the fibers at the outlet of the delivery roller which had been sucked into the perforation by their ends. These small belts without fabric inserts do not last long.